go to the download link , give ur email address and they will send u the key instantly. in the left side of that page u will see a link to downloads . click it and u will get the list of all avira products available for downloading . download avira antivir personal edition premium . almost 21 mb . if u r running antivir personal edition classic , uninstall it . restart, then run any registry cleaner . now install antivir personal edition premium . u will be asked for the key during the installation process , just browse and locate the key . continue installation . done . don't forget to update ............. good luck .